Levelling instrument



Dec. 29, 1964 K. NIELSEN 3,163,390

LEVELLING INSTRUMENT Filed March 13, 1961 United States Patent 3,163,390 LEVELLHJG INSTRUMENT Kaj Nielsen, Sirovlranten 9, Bagsvaerd, Denmark Filed Mar. 13, 1961, Ser. No. 95,282 7 Claims. (Cl. 248221) The invention relates to levelling instruments of the type having a pair of vessels that communicate with each other through a long flexible tube and wherein the vessels are of different horizontal cross-sections. The layer of the said vessels is preferably mounted on a supporting stand, whereas the other of the vessels is provided with an elevation scale. The larger vessel is supported by a pin by means of which it is vertically adjustable.

It is an object of the present invention to provide a simple and convenient but nevertheless sufiiciently accurately vertically displaceable mounting for the larger vessel. In accordance with the invention the pin of the larger vessel of the instrument is mounted so that it may slide on two plane surfaces angularly positioned in relation to each other inside a tube that is very wide in relation to the pin and has a recess on the lower edge of which an adjustment nut provided on the pin constitutes a support for adjusting the level of the vessel.

The said tube may suitably be incorporated in the supporting structure of the instrument. The mounting is thereby enclosed and safely protected against external forces whereas the supporting structure itself is used as a guide for the mounting. The said pin may be attached to the bottom of the vessel in a central or eccentric position and by means of an inner transverse wall or inner transverse pins the pin may be retained so as to establish sliding contact with the two angularly positioned guiding surfaces. A limitation of the possible turning movement of the vessel is not always required, especially not if the pin is attached to the vessel at a central point of the bottom. If, however, a lateral guide for the vessel is desired, this may be arranged within a ring which is attached to the upper end of the tube and has an inside diameter slightly exceeding the outer diameter of the larger vessel and which has such a height that it affords protection for the vessel against external mechanical forces.

A more satisfactory lateral guiding may be obtained according to the invention by providing on the pin, a web or finger having a free end which projects into position between two of the inner angularly positioned surfaces of the tube, of which surfaces at least one is different from the vertically guiding surfaces of the pin. The said Web or finger may then, if desired, cooperate with an additional finger to guide the vessel laterally in such manner that if the aforesaid protecting ring is retained the vessel will be unable to strike against the inner wall of the ring.

According to the invention the tube may furthermore be of square cross-section and the Web or finger may extend diagonally in the tube, whereby a very simple and suitable guiding mechanism for the larger vessel is obtained.

When the instrument is not in operation, it is convenient to place the elevation scale to which the smaller vessel is attached on some pins provided on the tube. One of the said pins may according to the invention have its rear end passed through the tube above the web so as to limit the upper adjustment of the larger vessel, such part of the pin as'. extends inside the tube preventing the web from moving out through the upper tube end. 7

The drawing shows an embodiment of a levelling instrument according to the invention.

3,163,399 Patented Dec. 29, 1964 FIGURE 1 shows such parts of the instrument as are essential for understanding the invention, viewed from the side, partly in section, and

FIGURE 2 is a section on the line IIII of FIGURE 1.

On a supporting stand (not shown) is mounted a vertical, for example displaceable, tube 1 of square crosssection. To the upper end of the said tube is attached a plate 2 which constitutes a segment of the bottom of a ring or frame 3.

A vessel 4 communicates through a long flexible tube 15 with a smaller vessel (not shown). The vessel 4 carries a downwardly directed pin 5 which is passed through a hole 6 provided in the plate 2 and projects into the tube 1 where the pin is kept in sliding contact with two inside, angularly positioned walls 7 and 8 (FIG- URE 2). The pin is provided with a web or finger 9 extending .diametrally into the opposite corner of the cross-section of the tube 1.

The pin 5 is provided at its lower end with a screwthread 10 cooperating with an adjustment nut 11 which extends partially into the tube 1 through a recess 12. The vessel 4 is closed and carries at its upper end a closing screw 13. At its lower end it is connected through a valve 14 to the long, flexible tube 15 which leads to the smaller vessel (not shown) of the instrument.

The vessel 4- is adjusted to the desired level by turning the nut '11, whereby the pin 5 and consequently the vessel 4 is raised or lowered. The vessel 4 is protected by the ring 3 and cannot be adjusted so much that it is-itself brought into contact with the inner wall of the ring. The movement of the vessel 4 is limited in the upward direction 'by the engagement of the finger 9 with a supporting pin 16 for a scale on which the aforesaid smaller vessel (not shown) is attached while the instrument is stored or transported. The pin 16 with its part 17 extends transversely through the tube 1.

The tube 1 may be of other cross-sectional shapes than that shown. If, for example, the tube is triangular in cross-section, the finger 9 should have an additional finger so that each finger may extend into a separate corner. Alternatively the finger 9 may be forked at its end, each of the forked parts projecting into each of the two other corners.

The tube 1 may be attached so as to be telescoped into a tube 18 fixed to the supporting stand by means of an attachment pin 19 with a handle 20. A coil spring 21 ensures that the pin remains inserted through a hole- 22 provided in the tube ll. If it is desired to lower the vessel 4 exactly 10 centimetres or a multiple of ten centimetres, the pin 19 is withdrawn from its engagement with the tube 1 by means of the handle 20, after which the tube 1 may be lowered and the pin 1? inserted into another hole 22 in the tube 1, the tube being provided with a series of holes 22, spaced at an exact distance of 10 centimetres apart.

What I claim and desire to secure by Letters Patent is:

1. Support structure for a leveling instrument, the support structure comprising a hollow member including a plurality of planar Walls defining corners for said member, a pin within the hollow member adapted for supporting a vessel of said leveling instrument, and means supporting the pinwithln the hollow member in contact with the walls at a corner of said member for adjustable movement of the pin lengthwise thereof, said means cooperating with the walls at another of said corners of said member to prevent rotation of'the pin about.

an axis extending lengthwise through said pin.

2. Support structurefor a leveling instrument, said support structure comprising: an elongated hollow member extending ina longitudinal direction, said member including longitudinal planar walls forming a cross section which is of polygon shape, a pin extending longia) tudinally within the hollow member, said pin being in sliding contact with a pair of intersecting Walls of the member for movement longitudinally of the member whereby a vessel may be adjustably supported on the pin, and means on the pin and in engagement With another wail of said memberfor cooperating therewith to prevent rotation of said pin relative to said member While permitting free longitudinal movement of the pin in said member.

3. For a leveling instrument having a vessel, support structure'coniprising: fourflat longitudinally extending Walls connected together to form a hollow member of square cross section, a pin of circular cross section adapted for supporting saidvessel and extending longitudinally within said member, means engaging said pin for supporting the same in slidable contact with a pair of intersecting walls and for adjusting the longitudinal position of said pin with respect to said membe and a Web on said pin and extending diagonally in said memberto contact the other of the walls of the member to stabilize the pin on the member with respect to rotation about a longitudinal axis while permititng substantially free longitudinal movement of the pin.

4. Structure as claimed in claim 7. comprising a further pin extending transversely through said member for contacting the web'on the pin to constitute a limit position for movement of the pin. 1 I

5. Support s ructure for a leveling instrument, the supportstructure comprising: .an elongated hollow member of rectangular cross section extending in a longitudinal direction, a pin slidably supported in a'corner of said rectangle for movement in a longitudinal direction, means engaging said pin for adjusting the longitudinal position thereofrelative to said member by sliding the pin in said member, whereby a vesselsupported by said pin may 'be adjusted relative to said member, and a web on said pin extending diagonally in said member to engage the member at a corner thereof which is diagonally opposite thecorner in which the pin is supported, whereby the pin is prevented from. rotating about a longitudinal axis through the pin While the pin is freely adjustable longitudinally with respect to the member.

6. Support structure for a leveling instrument, the support structure comprising: four flatwalls defining an elongated hollow member of rectangular cross section extending in a longitudinal direction, a pin of circular cross section within the member and in tangential contact with a pair of intersecting walls thereof for being supported in a corner oflsaid rectangular member for movement in a longitudinal direction, means engaging said pin for adjusting the longitudinal position thereof relative to said member by sliding the pin in said member and along said pair of walls, whereby a vessel supported by said pin may be adjusted relative to said member, and a web on said pin extending diagonally in said member to engage the other Walls of said member at the corner formed therebywhich is diagonally opposite the corner in which the pin is supported, whereby the pin is prevented from rotating about a longitudinal axis while the 'pin is freely adjustable longitudinally with respect to the member.

7. For a leveling instrument having'a vessel, support structure comprising: a hollow member including a plu rality of planar walls defining corners for said member, a cylindrical pin within the hollow member adapted for supporting the vessel, and means extending from said pin at an intermediate location thereof for contacting a pair of walls ata first corner of the member'and for holding the pin intangential contact with a pair of walls at another corner of the member such that the pin is wedged between said walls at the other of said corners and is prevented from rotating about an axis through said pin whilesaid pin is slidable along said axis.

References Cited in the file of this patent 7 UNITED STATES PATENTS France July 13, 

1. SUPPORT STRUCTURE FOR A LEVELING INSTRUMENT, THE SUPPORT STRUCTURE COMPRISING A HOLLOW MEMBER INCLUDING A PLURALITY OF PLANAR WALLS DEFINING CORNERS FOR SAID MEMBER, A PIN WITHIN THE HOLLOW MEMBER ADAPTED FOR SUPPORTING A VESSEL OF SAID LEVELING INSTRUMENT, AND MEANS SUPPORTING THE PIN WITHIN THE HOLLOW MEMBER IN CONTACT WITH THE WALLS AT A CORNER OF SAID MEMBER FOR ADJUSTABLE MOVEMENT OF THE PIN LENGTHWISE THEREOF, SAID MEANS COOPERATING WITH THE WALLS AT ANOTHER OF SAID CORNERS OF SAID MEMBER TO PREVENT ROTATION OF THE PIN ABOUT AN AXIS EXTENDING LENGTHWISE THROUGH SAID PIN. 